Messages in this thread | | | Date | Wed, 27 Aug 2008 07:30:20 +0200 | From | Brice Goglin <> | Subject | Re: [patch 3/4] x86: PAT Update validate_pat_support for intel CPUs |
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Pallipadi, Venkatesh wrote: > Default MTRR being UC for all reserved regions and drivers > wanting WC is very common situation and performance will be > affected when that ends up being UC access. > With pat disabled, drivers can set MTRR with WC in this case > and get the expected performance. >
Are you saying that drivers are supposed to check if PAT is disabled before deciding whether they need to setup a MTRR WC? If so, how to do we check that? Unless we get a way to know whether ioremap_wc() returned WC or UC, I will always keep the MTRR WC in myri10ge.
Brice
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